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    • By Achivai
      Hey, I am semi-new to 3d-programming and I've hit a snag. I have one object, let's call it Object A. This object has a long int array of 3d xyz-positions stored in it's vbo as an instanced attribute. I am using these numbers to instance object A a couple of thousand times. So far so good. 
      Now I've hit a point where I want to remove one of these instances of object A while the game is running, but I'm not quite sure how to go about it. At first my thought was to update the instanced attribute of Object A and change the positions to some dummy number that I could catch in the vertex shader and then decide there whether to draw the instance of Object A or not, but I think that would be expensive to do while the game is running, considering that it might have to be done several times every frame in some cases. 
      I'm not sure how to proceed, anyone have any tips?
    • By fleissi
      Hey guys!

      I'm new here and I recently started developing my own rendering engine. It's open source, based on OpenGL/DirectX and C++.
      The full source code is hosted on github:

      I would appreciate if people with experience in game development / engine desgin could take a look at my source code. I'm looking for honest, constructive criticism on how to improve the engine.
      I'm currently writing my master's thesis in computer science and in the recent year I've gone through all the basics about graphics programming, learned DirectX and OpenGL, read some articles on Nvidia GPU Gems, read books and integrated some of this stuff step by step into the engine.

      I know about the basics, but I feel like there is some missing link that I didn't get yet to merge all those little pieces together.

      Features I have so far:
      - Dynamic shader generation based on material properties
      - Dynamic sorting of meshes to be renderd based on shader and material
      - Rendering large amounts of static meshes
      - Hierarchical culling (detail + view frustum)
      - Limited support for dynamic (i.e. moving) meshes
      - Normal, Parallax and Relief Mapping implementations
      - Wind animations based on vertex displacement
      - A very basic integration of the Bullet physics engine
      - Procedural Grass generation
      - Some post processing effects (Depth of Field, Light Volumes, Screen Space Reflections, God Rays)
      - Caching mechanisms for textures, shaders, materials and meshes

      Features I would like to have:
      - Global illumination methods
      - Scalable physics
      - Occlusion culling
      - A nice procedural terrain generator
      - Scripting
      - Level Editing
      - Sound system
      - Optimization techniques

      Books I have so far:
      - Real-Time Rendering Third Edition
      - 3D Game Programming with DirectX 11
      - Vulkan Cookbook (not started yet)

      I hope you guys can take a look at my source code and if you're really motivated, feel free to contribute :-)
      There are some videos on youtube that demonstrate some of the features:
      Procedural grass on the GPU
      Procedural Terrain Engine
      Quadtree detail and view frustum culling

      The long term goal is to turn this into a commercial game engine. I'm aware that this is a very ambitious goal, but I'm sure it's possible if you work hard for it.


    • By tj8146
      I have attached my project in a .zip file if you wish to run it for yourself.
      I am making a simple 2d top-down game and I am trying to run my code to see if my window creation is working and to see if my timer is also working with it. Every time I run it though I get errors. And when I fix those errors, more come, then the same errors keep appearing. I end up just going round in circles.  Is there anyone who could help with this? 
      Errors when I build my code:
      1>Renderer.cpp 1>c:\users\documents\opengl\game\game\renderer.h(15): error C2039: 'string': is not a member of 'std' 1>c:\program files (x86)\windows kits\10\include\10.0.16299.0\ucrt\stddef.h(18): note: see declaration of 'std' 1>c:\users\documents\opengl\game\game\renderer.h(15): error C2061: syntax error: identifier 'string' 1>c:\users\documents\opengl\game\game\renderer.cpp(28): error C2511: 'bool Game::Rendering::initialize(int,int,bool,std::string)': overloaded member function not found in 'Game::Rendering' 1>c:\users\documents\opengl\game\game\renderer.h(9): note: see declaration of 'Game::Rendering' 1>c:\users\documents\opengl\game\game\renderer.cpp(35): error C2597: illegal reference to non-static member 'Game::Rendering::window' 1>c:\users\documents\opengl\game\game\renderer.cpp(36): error C2597: illegal reference to non-static member 'Game::Rendering::window' 1>c:\users\documents\opengl\game\game\renderer.cpp(43): error C2597: illegal reference to non-static member 'Game::Rendering::window' 1>Done building project "Game.vcxproj" -- FAILED. ========== Build: 0 succeeded, 1 failed, 0 up-to-date, 0 skipped ==========  
      #include <GL/glew.h> #include <GLFW/glfw3.h> #include "Renderer.h" #include "Timer.h" #include <iostream> namespace Game { GLFWwindow* window; /* Initialize the library */ Rendering::Rendering() { mClock = new Clock; } Rendering::~Rendering() { shutdown(); } bool Rendering::initialize(uint width, uint height, bool fullscreen, std::string window_title) { if (!glfwInit()) { return -1; } /* Create a windowed mode window and its OpenGL context */ window = glfwCreateWindow(640, 480, "Hello World", NULL, NULL); if (!window) { glfwTerminate(); return -1; } /* Make the window's context current */ glfwMakeContextCurrent(window); glViewport(0, 0, (GLsizei)width, (GLsizei)height); glOrtho(0, (GLsizei)width, (GLsizei)height, 0, 1, -1); glMatrixMode(GL_PROJECTION); glLoadIdentity(); glfwSwapInterval(1); glEnable(GL_SMOOTH); glEnable(GL_DEPTH_TEST); glEnable(GL_BLEND); glDepthFunc(GL_LEQUAL); glHint(GL_PERSPECTIVE_CORRECTION_HINT, GL_NICEST); glEnable(GL_TEXTURE_2D); glLoadIdentity(); return true; } bool Rendering::render() { /* Loop until the user closes the window */ if (!glfwWindowShouldClose(window)) return false; /* Render here */ mClock->reset(); glfwPollEvents(); if (mClock->step()) { glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); glfwSwapBuffers(window); mClock->update(); } return true; } void Rendering::shutdown() { glfwDestroyWindow(window); glfwTerminate(); } GLFWwindow* Rendering::getCurrentWindow() { return window; } } Renderer.h
      #pragma once namespace Game { class Clock; class Rendering { public: Rendering(); ~Rendering(); bool initialize(uint width, uint height, bool fullscreen, std::string window_title = "Rendering window"); void shutdown(); bool render(); GLFWwindow* getCurrentWindow(); private: GLFWwindow * window; Clock* mClock; }; } Timer.cpp
      #include <GL/glew.h> #include <GLFW/glfw3.h> #include <time.h> #include "Timer.h" namespace Game { Clock::Clock() : mTicksPerSecond(50), mSkipTics(1000 / mTicksPerSecond), mMaxFrameSkip(10), mLoops(0) { mLastTick = tick(); } Clock::~Clock() { } bool Clock::step() { if (tick() > mLastTick && mLoops < mMaxFrameSkip) return true; return false; } void Clock::reset() { mLoops = 0; } void Clock::update() { mLastTick += mSkipTics; mLoops++; } clock_t Clock::tick() { return clock(); } } TImer.h
      #pragma once #include "Common.h" namespace Game { class Clock { public: Clock(); ~Clock(); void update(); bool step(); void reset(); clock_t tick(); private: uint mTicksPerSecond; ufloat mSkipTics; uint mMaxFrameSkip; uint mLoops; uint mLastTick; }; } Common.h
      #pragma once #include <cstdio> #include <cstdlib> #include <ctime> #include <cstring> #include <cmath> #include <iostream> namespace Game { typedef unsigned char uchar; typedef unsigned short ushort; typedef unsigned int uint; typedef unsigned long ulong; typedef float ufloat; }  
    • By lxjk
      Hi guys,
      There are many ways to do light culling in tile-based shading. I've been playing with this idea for a while, and just want to throw it out there.
      Because tile frustums are general small compared to light radius, I tried using cone test to reduce false positives introduced by commonly used sphere-frustum test.
      On top of that, I use distance to camera rather than depth for near/far test (aka. sliced by spheres).
      This method can be naturally extended to clustered light culling as well.
      The following image shows the general ideas

      Performance-wise I get around 15% improvement over sphere-frustum test. You can also see how a single light performs as the following: from left to right (1) standard rendering of a point light; then tiles passed the test of (2) sphere-frustum test; (3) cone test; (4) spherical-sliced cone test

      I put the details in my blog post (https://lxjk.github.io/2018/03/25/Improve-Tile-based-Light-Culling-with-Spherical-sliced-Cone.html), GLSL source code included!
    • By Fadey Duh
      Good evening everyone!

      I was wondering if there is something equivalent of  GL_NV_blend_equation_advanced for AMD?
      Basically I'm trying to find more compatible version of it.

      Thank you!
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OpenGL glGetIntegerv(GL_NUM_EXTENSIONS, &NumExtension) doesnt work

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hello Ive been using Ubuntu Linux for a year now and Ive recently been working on an opengl app. anyways im making an opengl extensions wrapper but glGetIntegerv doesn't seem to be working.

GLint NumExtension = 0;
glGetIntegerv(GL_NUM_EXTENSIONS, &NumExtension);
std::cout << "NUM_EXTENSIONS = " << NumExtension << "\n"; // this line prints out "0"

basically im trying to get a list of supported extensions but this function doesn't seem to be doing anything. i cant use glGetStringi(GL_EXTENSIONS, i) if i don't know how Manny there is. which by the way glGetStringi(GL_EXTENSIONS, i) actually works fine. i through an arbitrary number in there and it gave me some function name.

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Are you sure you have an OpenGL 3.0 or later rendering context active? Are you sure there are no errors, implying that you really have zero extensions available?

edit: Err, well, I think I misunderstood your last paragraph for some reason. Apparently everything but querying the number works, so never mind the above. Still, check for errors after each and every function to see if you can narrow it down.

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thanks for the reply. my gpu is a "GeForce 6150SE nForce 430" i don't think it can support openGL3.0 i hope thats not a requirement for this function. as far as which functions causing the problem. those three lines of code have been copied and pasted line for line from my source. i changed the first parameter to some other supported macro and it sent back some value. moreover if i initialize NumExtensions with a number other than 0 and call glGetIntegerv. it wont change the value of NumExtensions. so the function doesn't seem to be doing any thing with my integer.

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crap is there any other way of getting that value from OpenGL? if not would it be safe to test if an extension exists by calling glXGetProcAddress and checking if it returns NULL like so.

if(glXGetProcAddress((GLubyte*)"SomeFunctionName") == NULL)
std:cout << "SomeFunctionName" << " Is Not Supported!\n";


PFNGLGETSTRINGIPROC glGetStringi = (PFNGLGETSTRINGIPROC) glXGetProcAddress((GLubyte*)"glGetStringi");
if(glGetStringi == NULL)
std:cout << "glGetStringi" << " Is Not Supported!\n";

so far the second has worked fine. i just want to know if this is a safe way of checking for Extensions.

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No, it is not safe. The function is only valid if the corresponding extension is reported as being supported, or if you have a sufficiently recent rendering context. Otherwise, the return value is not guaranteed to point to a properly implemented function. It may, for example, return some experimental function.

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Can you check the version using glGetString with GL_VERSION, I use this code below and I get version of 3.3, and the GL_NUM_EXTENSIONS returns a number for me and then I loop through all the extensions. This is C# but the calls to open gl functions are the same.

Also I noticed I use an int[] in my code and you use a pointer to an int, I dunno if that wouild make a difference.

// get version, vendor, renderer
string sVersion = StringUtility.GetStringFromIntPtr(RC.glGetString(GLEnum.GL_VERSION), 1024);
string sVendor = StringUtility.GetStringFromIntPtr(RC.glGetString(GLEnum.GL_VENDOR), 1024);
string sRenderer = StringUtility.GetStringFromIntPtr(RC.glGetString(GLEnum.GL_RENDERER), 1024);

// get supported extensions
int[] ext = new int[1];
RC.glGetIntegerv(GLEnum.GL_NUM_EXTENSIONS, ext);

for (int i = 0; i < ext[0]; i++)
IntPtr cstring = RC.glGetStringi(GLEnum.GL_EXTENSIONS, (uint)i);
string sExtension = StringUtility.GetStringFromIntPtr(cstring, 1024);

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Thanks for the reply zmg2b6. but brother bob said i cant get the number of extensions with OpenGL2.0 so i cant use the glGetStringi function because i don't know how Manny times to loop it.

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You can get the extension string with glGetString and GL_EXTENSIONS to get a list of extensions currently supported if you're having a 2.0 rendering context. It will return a space-separated list of all extensions, so search that string.

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